Fission-induced vaporization of UO 2 from a source and subsequent condensation on collectors exposed to fission fragment bombardment

Abstract

Fissionable thin films of UO 2 were irradiated in vacuum opposite thin carbon collector films. Vaporization of UO 2 due to fission fragment interaction with the source film occurs. The deposit on collectors has been identified as UO 2 by electron diffraction. A 200-Å-thick layer of carbon on the source film virtually eliminates vaporization. Fission fragment damage to carbon, platinum-coated carbon, and aluminum foil collectors manifests itself in the electron microscope image as holes and tracks. The damage to collectors appears to be a complex function of the distance between fragment and the free surface of the collector and of the energy transferred to the collector.